●●●●● ●●●● Records-sale-of ●●●●● ●●●● Described-b ●●0● Product Product Specificati pnce itemID Used-b Describ Sales Lineltem Store tem name 1 Contained-In Logs- completed 1 Houses Sale Started-by Manager time Paid-b itiated-by 4 Records-sales-on Payment Customer Ca ashier领域模型